1,431 research outputs found
An overlooked family-group name among bees: Availability of Coelioxoidini (Hymenoptera: Apidae)
Recent phylogenetic analysis of the family Apidae has applied the tribal name Coelioxoidini to the distinctive genus Coelioxoides Cresson, which has been thought to be related to Tetrapedia Klug. However, the nomenclatural status of such a family-group name has not yet been assessed. Herein, we determine that this family-group name is available and discuss its authorship and proposal date
Real sequence effects on the search dynamics of transcription factors on DNA
Recent experiments show that transcription factors (TFs) indeed use the
facilitated diffusion mechanism to locate their target sequences on DNA in
living bacteria cells: TFs alternate between sliding motion along DNA and
relocation events through the cytoplasm. From simulations and theoretical
analysis we study the TF-sliding motion for a large section of the DNA-sequence
of a common E. coli strain, based on the two-state TF-model with a fast-sliding
search state and a recognition state enabling target detection. For the
probability to detect the target before dissociating from DNA the TF-search
times self-consistently depend heavily on whether or not an auxiliary operator
(an accessible sequence similar to the main operator) is present in the genome
section. Importantly, within our model the extent to which the interconversion
rates between search and recognition states depend on the underlying nucleotide
sequence is varied. A moderate dependence maximises the capability to
distinguish between the main operator and similar sequences. Moreover, these
auxiliary operators serve as starting points for DNA looping with the main
operator, yielding a spectrum of target detection times spanning several orders
of magnitude. Auxiliary operators are shown to act as funnels facilitating
target detection by TFs.Comment: 26 pages, 7 figure
A new subgenus of <i>Heterotrigona</i> from New Guinea (Hymenoptera: Apidae)
A new subgenus is established within the Indomalayan stingless bee genus Heterotrigona Schwarz (Meliponini). Sahulotrigona Engel & Rasmussen, new subgenus, is distinguished from amongst other Heterotrigona, particularly the subgenus Platytrigona Moure, within which one of the two included species was previously placed. The subgenus presently includes two species from New Guinea: Heterotrigona (Sahulotrigona) paradisaea Engel & Rasmussen, new species, and H. (S.) atricornis (Smith), new combination. A key to the subgenera of Heterotrigona is provided and the species are tabulated, resulting in the following new combinations: Heterotrigona (Platytrigona) flaviventris (Friese), H. (P.) hobbyi (Schwarz), H. (P.) keyensis (Friese), H. (P.) lamingtonia (Cockerell), H. (P.) planifrons (Smith), H. (Sundatrigona) lieftincki (Sakagami & Inoue), and H. (Su.) moorei (Schwarz). The stingless bees of Papuasia are briefly summarized, and a key is presented to the genera and subgenera of Paupasian Meliponini
Revision of the bee genus Chlerogella (Hymenoptera: Halictidae), Part III: New records and a new species from Peru
This is the publisher's version, also available electronically from https://journals.ku.edu/index.php/melittology/indexA distinctive new species of the bee genus Chlerogella Michener (Halictinae: Augochlorini) is described and figured from central Peru (Santuario Nacional Pampa Hermosa). Chlerogella mabelae Engel, new species, is quite distinctive from other species of the genus and can be recognized by its sculpturing, coloration, and male terminalia. In addition, new Peruvian records for C. azurea (Enderlein) and C. rostrata Engel are appended
A new species of Liphanthus from Peru (Hymenoptera: Andrenidae)
The protandrenine bee genus Liphanthus Reed (Panurginae: Protandrenini) is currently known from Chile and Argentina. Â Liphanthus (Melaliphanthus) cuscoensis Gonzalez, Rasmussen, & Engel, new species, is described and figured from a male collected in Cusco, Peru, at 4167 meters of elevation. Â This finding represents the northernmost record for the genus and the fourth protandrenine species described from Peru. Â An updated key to the species of the subgenus Melaliphanthus Ruz & Toro is provided
Incasarus garciai, a new genus and species of panurgine bees from the Peruvian Andes (Hymenoptera: Andrenidae)
This is the publisher's version, also available electronically from https://journals.ku.edu/index.php/melittology/indexIncasarus garciai Gonzalez, Rasmussen, & Engel, a new genus and species of protandrenine bees (Andrenidae: Panurginae), is described and figured from a male collected in Ayacucho, Peru. Incasarus superficially resembles Liphanthus Reed in the narrow pterostigma and gonostylus articulated to the gonocoxite but it can be distinguished easily by the combination of two submarginal cells, the seventh sternum with apodemes and apical lobes broad, short, attached to a large disc, and the gonostylus long, about as long as the gonocoxite. Incasarus also resembles Rhophitulus Ducke and Heterosarus Robertson in the male seventh tergum with the distal margin medially projected, but it differs from both genera in the shape of the hidden sterna and genitalia, among other features
Self-regulation processes and health: The importance of optimism and goal adjustment
ABSTRACT This article discusses how self-regulatory models can be used to understand people’s response to health threats. The article begins with a general discussion of the principles and assumptions of self-regulatory models of behavior. Two distinct lines of research are then presented addressing two important processes of adaptive self-regulation. First, we provide a brief overview of the literature on optimism and adjustment to chronic disease and other health outcomes. Second, we present an overview of the process of disengagement from unattainable goals, focusing on recent research. We close by making recommendations for future research. The purpose of this article is to discuss some of the ways in which self-regulatory models of behavior can help us understand people’s responses to health threats. This article begins with a general discussion of a set of orienting assumptions and principles embedded in models of self-regulation of behavior, placing the heaviest emphasis on our own approach. We then describe two distinct lines of researc
Involvement of a putative intercellular signal-recognizing G protein-coupled receptor in the engulfment of Salmonella by the protozoan Tetrahymena
In an effort to investigate the molecular basis of protozoa engulfment-mediated hypervirulence of Salmonella in cattle, we evaluated protozoan G protein-coupled receptors (GPCRs) as transducers of Salmonella engulfment by the model protozoanTetrahymena. Our laboratory previously demonstrated that non-pathogenic protozoa (including Tetrahymena) engulf Salmonella and then exacerbate its virulence in cattle, but the mechanistic details of the phenomenon are not fully understood. GPCRs were investigated since these receptors facilitate phagocytosis of particulates byTetrahymena, and a GPCR apparently modulates bacterial engulfment for the pathogenic protozoan Entamoeba histolytica. A database search identified three putative Tetrahymena GPCRs, based on sequence homologies and predicted transmembrane domains, that were the focus of this study. Salmonella engulfment by Tetrahymenawas assessed in the presence of suramin, a non-specific GPCR inhibitor. Salmonella engulfment was also assessed in Tetrahymena in which expression of putative GPCRs was knocked-down using RNAi. A candidate GPCR was then expressed in a heterologous yeast expression system for further characterization. Our results revealed that Tetrahymena were less efficient at engulfing Salmonella in the presence of suramin. Engulfment was reduced concordantly with a reduction in the density of protozoa. RNAi-based studies revealed that knock-down of one the Tetrahymena GPCRs caused diminished engulfment of Salmonella. Tetrahymena lysates activated this receptor in the heterologous expression system. These data demonstrate that the Tetrahymena receptor is a putative GPCR that facilitates bacterial engulfment by Tetrahymena. Activation of the putative GPCR seemed to be related to protozoan cell density, suggesting that its cognate ligand is an intercellular signaling molecule
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